Entrance door finishing

[NewDIYer]

I would like to make best of the experience and skills from the members of this forum. So here I go:

About a couple of years ago I stripped the poly coat on my front door and re-coated it. I now see that the weather has led to the coating coming off and I need to do the strip and coat again.

Do I paint? If so, I would have to sand the door down, prime and paint.

Do I re-coat? What polyu (or other) coat is recommended? Is there a stripping process recommended other than chemical stripping?

Any advice is valuable.

Thanks.

PS - I can post pictures if needed.

[LCHIEN]

rather than just the weather the failure may be due to UV light deteriorating the finish. For an external door it is very important to pick a highly UV resistant finish and some polyurethanes and varnishes are better than others. I can't make a specific recommendation but I'll bet that's part of your problem since exterior door finishes should last longer than 2 years and are very much exposed to UV.

I'm sure others will make recommendations for specific products.

[cabinetman]

The type of exposure will determine how effective a finish will be. A door that receives direct sunlight and the elements of the weather is at the most risk. Covered alcoves provides good protection.

Protection is determined by the opacity and UV content of the finish.

Paint: Either in oil base or waterbase offers the most protection. A painted finish will require a maintenance regimen, and that can include sanding (possibly stripping), and recoating. Its a reflective finish.

Spar varnish/spar urethane: A translucent coating consisting of varnish resins, oil, and UV inhibitors. UV (ultra violet) inhibitors do just that, inhibit. They don't prevent or reflect, but absorb. In time, their effectiveness declines, and the finish will need maintenance. It will need sanding or stripping when the film becomes crusty, and can become separated from the wood. The onset appears to be a cloudy whitish haze. It can crack, bubble, and peel from the surface.

As a finish, it will impart an amber tone to a natural woodgrain, or a stain, due to the oil content. It has a longer (greater) oil ratio than an interior varnish or polyurethane. It never really hardens, but retains some elasticity to deal with the weather elements, i.e., temperature changes. It can take weeks or longer to fully cure.

Marine grade spars are very expensive and can require 5-7 applications as required by the directions. When they fail and they will, they are a PITA to refinish.

Oil types: Penetrating oils, such as Penofin, or GF Outdoor Oil, imbed into the pores of the wood, and with several applications offer some moisture and UV protection. There is very little abrasion resistance with these finishes. They can be high in UV additives, and can come in "clear" or tinted colors. They offer the minimum in maintenance by only needing a cleaning and another application. If the need is to see the wood grain, IMO these finishes are ideal for the preservation of the wood. They allow the natural transfer of air and moisture that is characteristic with wood doors.

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[pelligrini]

It's probably UV exposure more than weather. Even the UV resistant spar urethanes will break down over time.

If you can get it sanded down and looking good, the oil types might be your best bet. Paint works, but what woodworker wants to cover some nice woodgrain with paint?

Check out post 15 in this thread for some observations on the oil finishes: http://www.bt3central.com/showthread.php?t=55584&page=2